/*
* AUTHOR : lo0ker
* Problem : Foehn Phenomena
* source : https://oj.uz/problem/view/JOI17_foehn_phenomena
*/
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vi = vector<int>;
using pii = pair<int, int>;
#define pb push_back
#define all(x) begin(x), end(x)
#define sz(x) (int) (x).size()
const int MOD = 1e9+7;
struct FenwickTree{
vector<ll> val;
int n;
FenwickTree(int n){
val.resize(n);
this->n = n;
}
void update(int idx, int delta){
for(; idx < n; idx |= (idx+1)){
val[idx] += delta;
}
}
ll query(int idx){
ll ret = 0;
for(; idx >= 0; idx = (idx&(idx+1))-1){
ret += val[idx];
}
return ret;
}
};
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n, q;
ll s, t;
cin >> n >> q >> s >> t;
vector<ll> a(n+1);
for(auto &it : a) cin >> it;
ll ans = 0;
for(int i = 0; i < n; i++){
if(a[i] < a[i+1]){
ans -= s*(a[i+1] - a[i]);
}
else{
ans += t*(a[i] - a[i+1]);
}
}
FenwickTree ftree(n+1);
int l, r;
ll x;
for(int j = 0; j < q; j++){
cin >> l >> r >> x;
ll prev = 0;
ll al1 = a[l-1] + ftree.query(l-1);
ll al2 = a[l] + ftree.query(l);
ll temp = al1 - al2;
prev += (temp < 0) ? s*(temp) : t*(temp);
if(r < n){
ll ar1 = a[r] + ftree.query(r);
ll ar2 = a[r+1] + ftree.query(r+1);
temp = ar1 - ar2;
prev += (temp < 0) ? s*(temp) : t*(temp);
}
ans -= prev;
ftree.update(l, x);
ftree.update(r+1, -x);
al1 = a[l-1] + ftree.query(l-1);
al2 = a[l] + ftree.query(l);
temp = al1 - al2;
ans += (temp < 0) ? s*(temp) : t*(temp);
if(r < n){
ll ar1 = a[r] + ftree.query(r);
ll ar2 = a[r+1] + ftree.query(r+1);
temp = ar1 - ar2;
ans += (temp < 0) ? s*(temp) : t*(temp);
}
cout << ans << "\n";
/*for(int i = 0; i <= n; i++){
cout << a[i] + ftree.query(i) << " ";
}
cout << "\n";*/
}
return 0;
}
